As of 2023, 69% of adults and 81% of teens in the U.S. use social media. This study explores the immediate effects of social media consumption on executive functioning (EF) and emotion in college students, using a wearable fNIRS system to monitor brain activity in a naturalistic setting. Twenty participants were assessed pre- and post-social media use through EF tasks and emotion questionnaires. Results revealed 55% of participants were classified as addicted, with an average Instagram usage of 5 hours per week. Following social media exposure, significant impairments were observed in tasks like n-back and Go/No-Go, alongside altered brain activity. Specifically, increased medial prefrontal cortex (mPFC) activity indicated heightened cognitive effort and performance monitoring, while decreased dorsolateral prefrontal cortex (dlPFC) and ventrolateral prefrontal cortex (vlPFC) activity were associated with impaired working memory and response inhibition. Inferior frontal gyrus (IFG) activity reductions correlated with difficulties in inhibiting motor responses to No-Go stimuli. Emotional changes were minimal, except for reduced happiness in the control group. These findings highlight the negative impact of social media on EF, emphasizing the need for interventions promoting healthier digital habits.